The research project involves an assessment of the role of halogenated pyrimidine analogs in inducing neoplasia in Drosophila. Growth response to 5-bromodeoxyuridine treatment will be evaluated by tabulating the induction of supernumerary tissues and bristles on the adult wing, and BUdR-incorporated DNA will be examined by CsCl pycnography and pyrimidine isostich analysis. A biochemical analysis of analog treated and normal cells will include an investigation into the nature and function of "perichromatin granules" isolated from the nuclei.